Eartquake

The eartquakes are shakes in the litosphere
The bigger part of eartquakes is caused by sismic movements in the litosphere, a very thin part of the Earth.
The litosphere is divided by the tetonic plates. Those tetonic plates can contain oceans or earth.
One of the sismic movements is the subduction. It happens when a tetonic plate that contains water and one whit earth confrontate, the one whit water goes below the one whit earth.
When two oceanic tetonic plates or two continental encounter, they can do two things: they can bend or if they don't resist, they can break.
Also, when two tetonic plates are too lazy to do these things, they pass by, Say hello to each other and rub themselves because they're stupid.

The tetonic plates move because of the conviction, a spinning movement that happens in the atenosphere, and the magma does it to put the cold material down and the hot one up.
But some eartquakes are caused because of the volcans, if that's the case, ur fucked up. (*Sigh*, yeah, yeah, I'll explain it, don't worry).
When the conviction is too strong that breaks the litosphere, ir exites because its freedom and pushes the magma so strong that the magma desides to change its name to lava. But the lava colds when it gets out, and transforms to rock, also it's so generous that it compesates the poor volcan, making it bigger.
But the eartquakes also can be summoned when some asshole detonates a big-as-heck explosion.